Apparatus for forming fiber mats, including deckle boxes with white water return



1953 R. CHAPMAN 2,660,935

APPARATUS FOR FORMING FIBER MATS, INCLUDING DECKLE BOXES WITH WHITE WATER RETURN Filed Dec. 20, 1948 3 Sheets-Sheet 1 50 o 50 I fi 1 J I I 4/ J5 J6 46 7 i i 52 45 I I I 2 m I Z I 55 2 AW 6/ 57 L, T WL /6 80 60 v 9M5 l 5.

' INVENTOR.

9040/? Chqomcm %%...4 m 573m CHAPMAN APPARATUS FOR FORMING FIBER MATS, INCLUDING 3 Sheets-Sheet 2 Dec. 1, 1953 R.

DECKLE BOXES WITH WHITE WATER RETURN Filed Dec. 20, 1948 M II mmm WV WWI e Z 1 m o W I. d f w #Wl MUQi Dec. 1, 1953 R. CHAPMAN APPARATUS FOR FORMING FIBER MATS INCLUDING DECKLE BOXES WITH WHITE WATER RETURN 3 Sheets-Sheet 3 Filed Dec. 20, 1948 III INVENTOR. RALPH CHAPMAN QLAM AT TORNEYS Patented Dec. 1, 1953 APPARATUS FOR FORMING FIBER MATS, INCLUDING DECKLE BOXES WITH WHITE WATER RETURN Ralph Chapman, Corvallis, Oreg., assignor to Chapman Forest Utilization, Inc, Corvallis, reg., a corporation of Oregon Application December. 20, 1948, Serial No. 66,176

4 Claims. 1

The present invention comprises an improvement in equipment for forming a fibre mat by withdrawing white water from a slurry of fibres. The particular improvement herein disclosed comprises means whereby the level of liquid in theportion of a forming device beneath a forming screen may be brought back up to the lower surface of the formingscreen prior to the deposit of a charge of slurry above the forming screen, so as to avoid the irregular deposit of fibres heretofore produced by the initial rush of liquid through the screen as sometimes occurred in previously employed apparatus such as that disclosed in my copending applications, Serial No. 20,333 and Serial No. 20,334, both filed April 10, 1948, the latter now abandoned, wherein means are disclosed whereby suction is created in an elevated, closed tank to withdraw white water through a screen from forming apparatus comprising a movable deckle box frame positioned above the screen. The principal object of the present invention is to assure uniformity of fibre mats produced by equipment such as disclosed in the aforesaid applications by returning some of the white water to a stationary part of the forming apparatus below the screen prior to the deposit of a succeeding charge of slurry in the movable deckle box frame.

The present application is a companion application to my copending application, Serial No. 66,175, filed December 20, 1948, now U. S. Pat. 2,570,099, executed concurrently herewith and entitled Forming Tower With Sliding Valves.

A further object of the present invention is to provide means whereby the return of white water from an elevated white water tower to which it has been withdrawn by suction may be permitted under control of means for regulating the flow ,so that the apparatus may be adjusted to perform over a variable range of time, thus permitting the formation of various thicknesses of fibre mats.

A further object of the present invention is to provide a deckle box or forming vat comprising baffles so arranged beneath the screen that white water may be returned to the space beneath the screen in a very short space of time without hav ing the white water surge through the screen in some places.

The objects and advantages of the present invention may be more clearly understood by reference to the following specification taken in con nection with the accompanying drawings wherein like numerals refer to like parts throughoul'h while the features of novelty will be more readily ascertained by inspection of the appended claims, 1

In the drawings Fig. 1 is a somewhat schematic representation of a deckle box such a constructed in accordance with the disclosure of the aforesaid application, Serial No. 20,334, filed April 10, 1948, with improvements, combined with a white water tower such as disclosed in the concurrently executed application, Serial No. 66,175, filed December 20, 19%8.

Fig. 2 is a horizontal section throu h a cor-- tion of the apparatus taken substantially along line 22 of Fig 1;

Fig. 3 is a vertical section through the lower portion of the forming apparatus taken substantially along line 3-3 of Figs 1;

Fig. 4 is a horizontal section taken substantially along line 4-4 of Fig. 3; and

Fig. 5 is a schematic wiring diagramv of a control circuit for controlling operation of the various electrical components of the apparatus.

Althoughv many different types of forming a e paratus may have the present invention incorporated therein, the preferred type of forming vat comprises an. upper, rectangular deckle box frame [0 which is vertically reciprocated by suitable motive means shown only diagrammatically as Illa in Fig. 5 and toggles H as disclosed in said application, Serial No, 20,334. The frame I 0 is provided with a flange l2 around its lower edge in which a gasket may be seated, the gasket therein being adapted to press against a gasket seated in a peripheral flange I 3 on a lower, fixed portion 14 of the Vat. The upper frame [0 is lifted in timed relation to the movement of a forming screen l5 extending about a roll I6, upon r which the formed mat may be fed from the forming apparatus into succeeding equipment such as a cold press, or other apparatus. As di QlO in the aforesaid application, Serial No. 20,334, the screen I5 is horizontally supported within the forming apparatus by a grid ll of bar members supported within the lower portion Hi, The screen [5 may be fed longitudinally by means such as sprocket chains 18 attached to the edges thereof and extending about sprocket teeth on the drum [6 and other drums (not disclosed),

When a charge of slurry has been deposited in the upper frame l0 most of the water therein may be withdrawn through. the screen and through the lower section l4 upon the application of suction to pipes 29 and 2| leading from the lower portion l4 into an elevated, sealed white water "storage tank 22. Suction is created in the White water tank 22 by means of a continuously operat ing vacuum pump 23 connected to a pipe leading from the top of the tank. A vent pipe 24 is connected to the same pipe and is open to the at atmosphere when a vent valve is opened upon energization of a valve motor device 25. When the valve 25 is open vacuum cannot be created within the tank 22, but as soon as the valve is closed the vacuum commences to build up and in short order will be sufficient to lift the withdrawn white water into the tank 22.

A slurry tank is mounted upon the front face of the tank 22 and is adapted to receive a charge of thick slurry through a filling tube 31. As explained in the aforesaid application, Serial No. 20,333, the size of equipment necessary to produce and handle a large quantity of fibre slurry is reduced by having the slurry mixed with needed chemicals while its consistency is maintained relatively high, but best results of inter lacing the fibres on a forming screen are achieved when the consistency is fairly low. For this reason each charge into the deckle box frame iii is intimately mixed with the white water salvaged from the preceding charge to the extent found desirable by experiment, the excess white water being wasted or conducted to other apparatus for forming the thick slurry. In order that intimate mixing of the thick slurry with the white water may be achieved in rapid order the bottom of tank 39 is provided with a plurality of openings 33 adapted to be simultaneously opened and closed by a sliding gate valve 34 having a plurality of openings 35 therein, the gate being moved under control of a suitable valve operating motor device 353, and the white water from tank 22 is simultaneously discharged through a plurality of openings 3? in the lower portion of the front wall of the tank which are simultaneously opened and closed by a sliding gate valve 38 having a plurality of openings 39 therein, the valve being moved by a suitable valve operating motor as. The openings 33 are preferably arranged directly above the openings 3? so that the jets of white water strike the falling streams of thick slurry. The two bodies of liquid are thus thoroughly mixed and the mixture is then discharged through a closed flume 4! having a plurality of baflies 42 and 43 therein. The flume M is preferably the same width as the length of the deckle box and terminates over one edge of the deckle box so that a wide stream of thoroughly mixed liquid is discharged into the deckle box whenever the valve motors 35 and 4B are operated. A drain pipe 4%: is preferably provided at the angle between the lower wall of the flume and the first upwardly extending bafile 62, which drain pipe is under control of a valve 5 and suitable valve motor device 41. The valve 46 is closed when the slurry is being discharged but it is desired that the valve be opened simultaneously with the closing of valves 36 and 38 so as to reduce the after-ilowof fluid which might drip onto the wet mat before it is discharged from the deckle box.

The extent to which white water is retained within the tank 22 is controlled by a vertically adjustable overflow funnel 5D, the lower end of which extends through an over-size opening 5! in the bottom of the tank into a large, vertical, overflow pipe 52. The pipe 52 terminates in a reducer 53 which is connected to the upper end of an elbow 54, the horizontal arm of which is connected to a drain pipe through a check valve 55 of any suitable type adapted to be closed as soon as a vacuum is drawn in the tank 22 when'the valves 25, 3% and 3B are closed and charge is present in the deckle box iii. A white water return tube 51 is connected to the bottom of 4 the elbow 54 and extends horizontally into the lower portion Hi of the deckle box. Accordingly, whenever there is fluid present in the deckle box some of the fluid will be withdrawn through the return tube 51 and the vertical pipe 52 into the tank 22 through the annular space 5! surrounding the stem of the funnel 50. The converse is true in that whenever the vacuum is broken in tank 22 some fluid may escape back into the lower portion i l from the column of fluid standing in the overflow pipe 52 or the funnel 5i] and also through the annular space surrounding the stem of the funnel. The reducer 53 directs the flow into the mouth of the tube 51 which is substantially coaxial with the overflow tube. At a point further along the curve of the lower surface of the elbow 54 a second white water return tube 5-3 extends into one of the white water elevating pipes (in this case pipe 28) so that the water which can escape through the annular space 5% is substantially all returned to the bottom part of the deckle box when the vacuum breaks. The number and sizes of the white water return tubes may vary, the present disclosure being of two tubes such as 51 and 58 which have sufficient capacity, together with the white water standing in the tubes 20 and 2! and the lower portion of the deckle box when the vacuum breaks, to refill the lower portion of the deckle box back to the level of the screen I5, for any thickness of wet mat commercially produced at the present time. If more fluid should be needed a third tube might extend to the elevating pipe 2i, or he size of either or both tubes 5'? and 58 might be increased. In order to adjust the return flow a valve 53 is provided in at least one of the return tubes, the same being of the regulating type and adjustable through the medium of a hand wheel iii. Adjustment of valve 60 is provided so that for any timing resulting in the production of any desired thickness of wet mat the return fiow can be regulated to bring the liquid level back to the screen.

Within the deckle box portion Hi there is provided a baflle 55 extending from the side thereof above the inlets to the pipes 20, 2! and 5'! and from end to end of the deckle box, the baflie lying at an inclination downwardly and inwardly into the interior of the lower portion. The result of providing the baffle is that the vacuum will remain unbroken until the water level in the portion Hi reaches the lower lip of the baffie. At this point air begins to pass through the wet mat disposed on the screen 15 and will be drawn through the tubes 29, 2| and 51. The air which can be drawn through the mat cannot exceed the capacity of the pump so that the vacuum will remain sufficient to hold check valve 56 closed as long as vent valve 25 remains closed. A pressure differential switch 66 is preferably placed on the upper surface of one of the white water elevating pipes, in this case pipe 29. Many such switches are available, hence the details are not hereindisclosed. The switch 56 is arranged in a control circuit to be presently described whereby upon the rise in pressure when air passes through the mat action of other control means is initiated.

The first function of the pressure difierential switch 66 is to control the actuation of the deckle box frame elevating mechanism including motor ma. As disclosed in the aforesaid application, Serial No. 20,333, a control circuit is provided whereby the elevation of the deckle box frame Hi to a sufficient height to permit withdrawal of AQQQQQ 5 the termed wet mat causes actuation of screen feeding mechanism whereby the-portion of the screen holding the formed mat is fed forwardly out of the deckle box and into succeeding mech: anism. As soon as the screen is arrested after having traveled the required distance to place a fresh section of screen within the oleckle box, the upper frame I is lowered to form a complete enclosure with the lower portion M. The con: trol circuit of the present invention will now he explained. Referring to Fig. 5, it is apparent that current is supplied to the control circuit through a pair of supply lines It! and 1.03. Con,- nected between the supply lines is a line H35 in.-

cluding pressure diiTerentia-l switch .66 and a timer controlled relay m. The timer controlled relay controls a switch [99 a i-ine H I connected between the supply lines, line H l containing motor [Ba previously mentioned.

A bracket 80 on frame it supports a movable contact H3, and a bracket 8| on a fixed support holds a fixed contact 4 l5. ontacts H3 and H constitute a switch in a line H? connected be? tween the supply lines, line H'l containing a first timer controlled relay H9 and a second timer controlled relay I21. Timer controlled relay H9 controls a switch I23 in a line 125 connected to the supply lines, line 125 containing motor 4! for controlling valve 46. i imer controlled relay 121 controls a switch I21 arranged in a line 12:; con.- nected to the supply lines. Gonnected in line H5 in parallel relation are motors 25, 3 6 and .45.

The timer controlled relays are of conventional construction, and hence the detailed construct-ion need not be given. It is suiiicient to say that each 1 is of the type adapted to be intermittent-1y energized, and operable during each period of en ergization to energize a relay associated there.- with for a shorter time than the period of enerrgization of the timer, and upon termination of the period of energization of the timer to automatically reset itself to be in condition for a subsequent cycle of operation.

The operation of the control circuit is as fol lows. It may be assumed that switch -56 is open and that a charge of slurry has been deposited in the deckle box frame til and water is'being drawn out through conduits 2G and 57. Timer controlled relay Ill! is de-energized and thus switch 109 is open. Motor ifla is thus de-energized, and therefore the deckle box frame It remains resting on fixed deck'le box portion 44 and thus contacts H3 and H5 are in engagement. Timer controlled relays H9 and it are thus energized, but at this time in positions for deenergizing the associated relays, so that switches 123 and I2? are open.

When the vacuum first breaks, and is sensed by pressure differential switch 655, the switch closes to energize timer controlled relay llll'. Timer controlled relay M11 is set to immediately close switch I09 to thus energize motor 19c and cause declgle box frame lil to be elevated.- to separate contacts H3 and H5 and ,thus deaentlgize time c ntrol relays 9 and 12L .dwitth 343 n 2? remain p Wh le t im cont ol d lays at all reset msel es- .A so n as the decide hex f ame is sufiicient elevated, the screen is moved to remove the Wet mat. a fresh section of screen is in position, the screen is arrested and the deckle box frame returned. As the declrle box frame descengls, contacts H3 and H5 are brought into en g ment, nd a number .of .eyents occur. First, timer controlled relay 1-131. is energized and is set o imm di ely nergize it r lay and thus sense openi g v0f switch 1.09170 thus deaenereize mote;- dlla. Also closing-of switches H 3 and M15 renew gizes the reset timer controlled relays H13 and .1 21, timer .controlledrelay :l'2l :being set 1130 lim .mediately energize its relay and thus closelswitch 121, while timer controlled relay MES :15 .set 5130 delay energization of its relay and thus switch 1'23 remains open. zlosingof switch zl:2=l eauses .energization of motors 26, 235.6 and 4.0 so that a slurry charge is formed in and passes downfilume Al, while return water flows into box M. Th yalve 56-0 is so regulated with respect :to the riming ,of the .cycle that :the return flow into the fixed .portion L4, while white water and slurry are -being discharged into (the .deckzl TbQX is suflicient to :bring the level :back to the bottom of the .screen 15 just before the first of themix more hits the stOp .of the screen. For {any {thickm s f w t mat, the system may be accur tel balanced .so that the water strikes :both sides of the screen at-thesame instant.

A short time thereafter, timer controlled relay l2! de-energizes its relay to open switch J2?! and thus deeenergize motors :26, 3.6 and All, .50 th gate M. gate 3,8, and went yai e 2.5 ar closed. Simultaneously with this actio iiil 'lel' controlled relay He functions to energize its relay o clos switch 1:23 vso that motor M is energized to prev .dr ppineef fluid from time 4 I,-

In order to prevent sur n f the white Wa er through the screen a series of lea-fi es are arranged in the interiorof the l we p ti n M. The halffi s n eferaly comp i e a horizon al bafile 10 ex t ndin partial y across the deckle .box and partially len thwise thereof at a level slightly below the gri The horizontal bafile is preferably provided with a plurality of openin Fll throu h ch some liquid may now. A -longitudinally extending strap 72 is mounted on the lower surface of the home 10. and a p u ality of diagonally disposed, vertical anes .13 extend therefrom to the bottom ll .of the ortion M for slowin down the wate returnin th ough the pipe 25 and ube 5.1, A er iyal end loaflle. It xtends from the rear edge of hom 10 to a point slightl above he lower wall of the portion It. It is preie re that the anes 13 opposite pipe .23! slant tow rd th vanes nnosite tube 5; and the meeting P int etween the tw sets .Of vanes be .disposed between tw of the openings l so as to Preve t u ward surging oi the returned white water. llarious oth r r an em nts of bellies ma beprovided Without dep rtin fr m themesent nvention, th sole requi ite being thatv the water be pre ented surgin upwardly through p tions o th screen and b caused to return ouietly t the level of the bottom of the screen.

Havin illustrat d and described a pref rr d mbod m n f the mVenti Ii, .it should be app rent to tho skilled in th art that the inven tio permits o modificatio in detail and arran ement, l claim my invention all such modificati ns some Within the true spirit and scope .of the arn ndedelaims.

.I claim:

*1, Apparatus for forming a fibre mat by with drawing white water from a slurry .of fibres, com pri ing a ierming yat including an upwardly oath, upper part into which a char e of slum-y may he dir cted and lower nart through which whitewater may b drawn. a creen separatin said upper and lower parts, an elevated, sealed, white water storag t nk, first conduit means connecting the top of said tank to the lower part of said vat, said first conduit means extending horizontally from the lower part of said vat and then upwardly GO said tank, means for creating a vacuum in said tank to withdraw white water from slurry deposited in the upper part of said vat through said screen, the lower part of said vat, and said first conduit means into said tank whereby to form a mat of fibres on said screen, overflow means including an overflow funnel in said tank, an outlet from said funnel, and an outwardly opening check valve in said outlet for sealing said overflow means when a vacuum is drawn in said tank, operable to divert a portion of the elevated white water from said tank, second conduit means leading from the bottom of said tank to the lower part of the vat whereby the remainder of the elevated white water may return to said lower part'when the vacuum in said tank is broken, a vent valve communicating with said tank above said overflow funnel, and means responsive to the lowering of the liquid level in said vat to a point beneath said screen for opening said vent valve.

2. Apparatus for forming a fibre mat by withdrawing white water from a slurry of fibres, comprising a forming vat including an upwardly open, upper part into which a charge of slurry may be directed and a lower part through which white water may be drawn, a screen separating said upper and lower parts, an elevated, sealed, white water storage tank, large conduit means connecting the top of said tank to the lower part of said vat, said large conduit means extending horizontally from said lower part of the vat and then upwardly to said tank, means for creating a vacuum in said tank to withdraw white water from slurry deposited in the upper part of said vat through said screen, the lower part of said vat, and said large conduit means into said tank whereby to deposit a mat of fibres on said screen, overflow means including an overflow funnel in said tank, an out let from said funnel, and an outwardly opening check valve in said outlet for sealing said overflow means when a vacuum is drawn in said tank, operable to divert a portion of the elevated white water from said tank, second conduit means leading from the bottom of said tank to the lower part of the vat whereby the remainder of the elevated white water may return to said lower part when the vacuum in said tank is broken, a vent valve communicating with said tank above said overflow funnel, and means responsive to the lowering of the liquid level in said vat to a point beneath said screen for opening said vent valve, said second conduit means being constant- 1y open so that some white water is elevated therethrough into said tank as long as suflicient vacuum exists.

3. Apparatus for forming a fibre mat by withdrawing white water from a slurry of fibres, comprising a forming vat including an upwardly open, upper part into which a charge of slurry may be directed and a lower part through which white water may be drawn, a screen separating said upper and lower parts, an elevated, sealed, white water storage tank, large conduit means connecting the top of said tank to the lower part of said vat, said large conduit means extending horizontally from said lower part and then upwardly to said tank, means for creating a vacuum in said tank to withdraw white water from slurry deposited in the upper part of said vat through said screen, the lower part of said vat, and said large conduit means into said tank whereby to deposit a mat of fibres on said screen, overflow means including an overflow funnel in said tank, an outlet from said funnel, and an outwardly opening check valve in said outlet for sealing said overflow means when a vacuum is drawn in said tank, operable to divert a portion of the elevated white water from said tank, second conduit means leading from the bottom of said tank to the lower part of the vat whereby the remainder of the elevated white water may return to said lower part when the vacuum in said tank is broken, a vent valve communicating with said tank above said overflow funnel, and means responsive to the lowering of the liquid level in said vat to a point beneath said screen for opening said vent valve, and a regulating valve in said second conduit means for controlling the rate of flow therethrough.

4. Apparatus for forming a fibre mat by withdrawing white water from a slurry of fibres, comprising a forming vat including an upwardly open, upper part into which a charge of slurry may be directed and a lower part through which White water may be drawn, a screen separating said upper and lower parts, an elevated, sealed, white water storage tank, first conduit means connecting the top of said tank to the lower part of said vat, said first conduit means extending horizontally from said lower part and then upwardly to said tank, means for creating a vacuum in said tank to withdraw white water from slurry deposited in the upper part of said vat through said screen, the lower part of said vat, and said first conduit means into said tank whereby to form a mat of fibres on said screen, overflow means including an overflow funnel in said tank, an outlet from said funnel, and an outwardly opening check valve in said outlet for sealing said overflow means when a vacuum is drawn in said tank, operable to divert a portion of the elevated white water from said tank, second conduit means leading from the bottom of said tank to the lower part of the vat whereby the remainder of the elevated white water may return to said lower part when the vacuum in said tank is broken, a vent valve communicating with said tank above said overflow funnel, and means responsive to the lowering of the liquid level in said vat to a point beneath said screen for opening said vent valve, said second conduit means comprising a large, vertical portion depending from said tank, and said overflow funnel comprising a lower portion extending loosely into said large, vertical portion whereby white water may enter said second conduit means around the lower end of said funnel as well as over the upper edge of said funnel.

RALPH CHAPNIAN.

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